Alcohol Consumption Can Damage Hearing

It is well established that long-time alcohol consumption can cause brain damage that results in cognitive deficits, but research has found that cumulative, life-long alcohol consumption can cause damage to the brain's central auditory pathways, which results in hearing loss.

One study found that damage to the central auditory pathways can occur in even low-risk "social" drinkers—as well as moderate and heavy drinkers—as their cumulative, life-long alcohol consumption increases. In fact, social drinkers appear to be significantly more sensitive to an increase in cumulative alcohol consumption compared to moderate or heavy drinkers.

Nerve Damage Causes Hearing Loss

The German researchers who found the link between low-risk drinking and auditory deficits were quick to point out that their finding does not imply that low-risk drinkers are more at risk of hearing damage than heavier drinkers because the heavier drinkers with high life-long alcohol consumption have a larger amount of damaged nerves.

"It is an issue of 'saturation,'" the University of Ulm researchers concluded. "For each unit of further alcohol consumption, the absolute amount of nerves damaged ​for both kinds of drinkers is the same. However, the relative change of brain damage and subsequent further degradation of the hearing performance in the brainstem due to alcohol consumption will be significantly higher for drinkers with lower life-long alcohol consumption than for those with high life-long alcohol consumption."

Brainstem Auditory Evoked Potentials Evaluated

To measure the auditory damage that alcohol can cause, the German researchers evaluated the brainstem auditory evoked potentials (BAEPs) in their study subjects.

BAEPs measure how certain parts of your brain are processing auditory stimuli. In response to sound, a particular current response is activated, which can be detected by electrodes.

Heavy Drinkers and Social Drinkers

If there are defects in the transmission of these brain currents that affect the amplitude and/or latency of the current response, it can be detected by means of BAEP.

The researchers examined two groups of males, 19 with head and neck tumors who were considered heavy drinkers and 19 plastic surgery patients who were considered social drinkers. The groups were age and nicotine-matched.

The subjects were questioned about their alcohol use, given blood tests and hearing examinations. Recordings and evaluation of BAEPs were obtained.

Central Auditory Pathways Damaged

The results found that cumulative, life-long alcohol consumption affected BAEP latencies in both groups, indicating damage to central auditory pathways, resulting in hearing loss.

It should be noted that the results of the German study appear to conflict with other studies that have found that low or moderate alcohol consumption does not influence the risk of hearing loss, even in older males. In fact, one study found that moderate alcohol consumption had a modest protective effect on hearing loss, whereas heavy drinking was associated with hearing loss.

Since there are discordant results among many of these studies, the interpretation of these results should be viewed with caution. Additionally, although standard hearing tests do not readily measure the central auditory tracks, they do give very useful information about the hearing that is very important in day to day activities.

Damage Not Detected With Standard Tests

However, the other studies used standard hearing tests to determine hearing loss, rather than measuring defects in the central auditory tracks. These defects, the German researchers wrote, cannot be as readily detected by commonly used hearing tests.

Not only does life-long alcohol consumption cause overall brain shrinkage—in the cerebral cortex, hypothalamus, and cerebellum—that can result in multiple neurological defects, it can also potentially inflict damage on central auditory pathways, which can result in some hearing loss.